Chosen Solution
So I was a tv show on a website and it was on full screen. When I was done I exited full screen and entered another tab. When I entered the tab the bottom half (more than half actually) of the screen turned black and I tried to reset things and I did many things and it still doesn’t work.
Ouch! Not good ;-{ If the laptops screen stays that way when showing the desktop and you’ve tried an external display which doesn’t show any problems:
Your LCD display driver logic likely has a problem. This logic is part of the LCD its self and not repairable, or the LVDS cable is damaged. You’ll need a new lid assembly as these displays are not really serviceable. If the external monitor is showing the same problem you have a logic board issue. Did your system get wet or sat on a wet surface at some point?